Monday, October 13, 2014

Far above Cayuga's waters - my alma mater! - there are some excellent scientists using CRISPR to engineer mutations in mice. This paper is from John Schimenti's lab at Cornell and I believe it contains the most thorough review of mouse CRISPR engineering to date.

More than merely a review article, it has some additional new data from this group. They tested whether inhibition of the NHEJ pathway could enhance efficiency of CRISPR-mediated homology-directed repair, since these pathways compete following CRISPR cleavage; this was based on similar experiments done in Drosophila using ZFNs to do HDR. The answer seems to be yes, it helps in mouse embryos as well. The compound they used was SCR7, an inhibitor of ligase IV (a key player in NHEJ). Crucially, it seems that SCR7 can be applied directly to mouse embryo culture media with minimaltoxicity. Go to Table 2 for the result suggesting a shift in balance from predominantly NHEJ alleles toward more HDR alleles.